Problem: Add. $8.51 + 71=$
There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths Hundredths ${8}$ $.$ ${5}$ ${1}$ $7$ $1$ $.$ ${0}$ ${0}$ Because ${71}$ is a whole number, we can add a decimal point and two $0$ 's behind to make the columns align. Now, let's add each place value column. Tens Ones $.$ Tenths Hundredths ${8}$ $.$ ${5}$ $1$ $+$ $7$ ${1}$ $.$ ${0}$ $0$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $7$ $9$ $.$ $5$ $1$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &({8} + {71}) + {0.51}\\\\ &=79 + {0.51}\\\\ &=79.51 \end{aligned}$ $8.51 + 71=79.51$